The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A051592 Numbers n such that n!!!!!!-1 is prime. 3
 3, 4, 6, 12, 14, 54, 74, 102, 114, 302, 318, 366, 614, 1178, 1188, 3110, 7284, 21432, 21906, 25848, 29882, 38618, 41990, 84510, 86022 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS n!!!!!! = n(n-6)(n-12)(n-18)... The search for multifactorial primes started by Ray Ballinger is now continued by a team of volunteers on the website of Ken Davis (see link). LINKS Ray Ballinger, Status of Search for Multifactorial Primes Ken Davis, Status of Search for Multifactorial Primes Ken Davis, Results for n!6-1. MATHEMATICA MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]]; Select[Range[0, 1000], PrimeQ[MultiFactorial[#, 6] - 1] & ] (* Robert Price, Apr 19 2019 *) CROSSREFS Cf. A085158 (sextuple factorials), A085150. Sequence in context: A294144 A136243 A250985 * A044843 A293593 A024373 Adjacent sequences:  A051589 A051590 A051591 * A051593 A051594 A051595 KEYWORD hard,nonn AUTHOR EXTENSIONS Edited and extended by Hugo Pfoertner, Jun 23 2003 Corrected and extended by Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 9 17:13 EDT 2022. Contains 356026 sequences. (Running on oeis4.)